Electronic cameras using solid state image sensing devices such as a charge coupled device (CCD) have been receiving increased interest as a potential replacement for the universally accepted silver halide film type camera. Within the electronic camera, the optical image is converted to electrical signals, which are then stored in various types of memory devices. These memory devices can then be addressed at a later date to redisplay the image. They may also be addressed for purposes of transferring the stored image signals to another type of storage device such as a video tape. Some electronic cameras also provide a single image display device, which is generally located on the back of the housing, to provide the photographer with a captured image that may be viewed for purposes of determining if the image should be retained.
A patent of interest for its teaching in this area is UK patent application GB No. 2,089,169A published June 12, 1982, wherein a solid state still camera captures images and, with the use of a high-speed A/D converter, converts the images for storage in a temporary memory. The temporary memory can then be downloaded into a larger, more permanent solid state memory of the type that can hold more than one picture. The patent describes a magnetic bubble memory as being one form of larger, permanent solid state memory. Others mentioned are a removable memory chip and/or memory (magnetic) cassette. Viewing of the stored images can then be accomplished by addressing the permanent memory store with appropriate electronics and displaying the addressed signal bits.
Another device of interest is disclosed in Japanese patent application No. 55-153581 entitled "Electronic Camera" by N. K. Kogyo et al. In that application, the camera captures the image into a solid state storage means and provides a feature wherein the photographer may access the storage means to output to a display device the image stored therein. After observing the image and making an evaluation, the photographer either erases the image and/or restores the image into the storage device.
Two additional patents of particular interest are U.S. Pat. No. 4,420,773 entitled "Electronic Photographic Camera" by K. Toyoda et al. and U.S. Pat. No. 4,456,931 entitled "Electronic Camera" by K. Toyoda. Both of these patents relate to devices similar to those previously described with the additional feature in U.S. Pat. No. '773 being that the memory unit is contained in a physically detachable module which may removed from the camera and brought to further image processing apparatus. In U.S. Pat. No. '931, the memory unit is also detachable from the camera unit and can be connected to an external memory device such as a video tape recorder.
The cameras discussed in the aforementioned patents also each have the ability to display one image of stored data on a display that is affixed to the back portion of the camera housing.